A protocol with potential

IEC 61850 is an emerging protocol for the energy industry. Unlike earlier protocols, the technical approach makes it flexible and open to future requirement changes. It seems that it is slowly but surely becoming the international standard for power substation automation systems, and the goal of this article is to help understand what IEC 61850 is.

IEC 61850 defines the communication between devices in the substation and the system requirements which are related to this substation and those devices. In addition to purely defining communication protocols, the standard supports substation automation functions as well as their engineering.

There are over 50 protocols worldwide for substation automation. But, IEC 61850 is the only one that provides a standardised method of communications and integration. Its first goals is to support systems built from devices coming from multiple vendors. Those devices are named intelligent electronic devices (IEDs). They are networked together to perform protection, monitoring, automation, metering and control.

To achieve maximum benefit from this emerging protocol, it is essential to understand what it has to offer, how it is different from previous standards and what it provides to end users.

Capabilities

All these IEDs, inside a substation or even across an entire power network, are communicating in order to provide data gathering and setting capability as well as remote control. The fact that multiple IEDs are sharing data or control commands, results in new distribution protection, control and automation functions. This has the potential to supersede and eliminate much of the dedicated control wiring in a substation, plus costly special purpose communication channels between the stations and power network.

With IEC 61850’s standardisation of data acquisition and description methods, integration efforts are reduced. This standardisation enables the integration of the equipment and systems for controlling the electric power process into complete system solutions. This is necessary to support utilities’ processes. It ensures interoperability of equipment and systems by providing compatibility between interfaces, protocols and data models.

This protocol also meets utilities’ requirements for long term system expandability. Not only does it enable utilities to combine products from a variety of manufacturers, but it also affords users long term exchangeability of equipment to simplify parts stocking.

All of these factors contribute to time and cost savings as well as reducing the complexity of managing facilities.

This standard not only provides a device to device network, but it is also a station to station network. It transports important information from one substation to another, which is critical during power outages.

Differentiators

IEC 61580 is the only standard that meets the ever increasing demand from utility companies worldwide for compatibility of an installed base of control equipment from multiple vendors.

Since the protocol is Ethernet-based, it makes use of common and familiar tools and devices already present in utility business networks. This means each node on the network operates as a client to control the network and to talk to all the servers or slaves on the network. Since those slaves are typically IEDs that control the transformers and switchgear in the substations, they collect a lot of data that has to be read.

Unlike many other protocols, which do not have files and historical type transfer files, IEC 61850 enables files to be brought up from the IEDs to a Supervisory Control and Data Acquisition (SCADA) system to provide information on system activity. More importantly, it enables offline trending.

Unlike online trending where update rates might be as long as a second, offline capabilities provide data in milliseconds so that it can be saved and brought up for review and comprehensive analysis. To define the process data of servers (which provide data), IEC 61580 relies on object oriented programming, rather than traditional programming. Since object orientation emphasises data, not procedure, it affords users ease of modification and flexibility in adapting to changes of his business needs. Code and data are merged into one ‘object’. So, all the information and functionality information resides in one place. A device ‘publishes’ and sends information by multi-casting, and only devices that are ‘subscribers’ for this particular information receive this message.

End user benefits

The standard provides users with the ability to know in advance and predict how data will be moved and identified between clients and services from any manufacturer. With this predictability, integration is simplified.

With the client/server architecture of IEC 61850, intelligence moves closer to the process and eliminates the bottlenecks of classic master/slave architecture. The client controls the data exchange making client/server communication very flexible in terms of the data to be transmitted.

The protocol speeds the time critical exchanges of information. This way, it meets the safety requirements of several automated functions in a substation automation system.

The intended result is a seamless communication architecture for utilities. Since IEC 61850 has high impact on the investment and operation of power systems, the utilities and electrical energy substation on industrial sites will actively consider the standard as well as the suppliers.

When implementing IEC 61850, it is imperative to work with suppliers who provide the high level of technical and application expertise that is critical to achieve optimal results. Supplier support ensures ease of configuration and commissioning, saves time, increases efficiency, provides faster return on investment and enables users to gain the advantages of the strengths of IEC 61850’s potential.

ProSoft Technology has provided more detailed information and clarification on the IEC 61850 protocol which can be viewed on our website at www.connectingindustry.com/energymanagement.